On 11:15 am, p...@boddie.org.uk wrote:
On 22 Nov, 05:10, exar...@twistedmatrix.com wrote:
"tail -f" is implemented by sleeping a little bit and then reading to
see if there's anything new.
This was the apparent assertion behind the "99 Bottles" concurrency
example:
http://wiki.python.org/moin/Concurrency/99Bottles
However, as I pointed out (and as others have pointed out here), a
realistic emulation of "tail -f" would actually involve handling
events from operating system mechanisms. Here's the exchange I had at
the time:
http://wiki.python.org/moin/Concurrency/99Bottles?action=diff&rev2=12&rev1=11
It can be very tricky to think up good examples of multiprocessing
(which is what the above page was presumably intended to investigate),
as opposed to concurrency (which can quite easily encompass responding
to events asynchronously in a single process).
Paul
P.S. What's Twisted's story on multiprocessing support? In my limited
experience, the bulk of the work in providing usable multiprocessing
solutions is in the communications handling, which is something
Twisted should do very well.
Twisted includes a primitive API for launching and controlling child
processes, reactor.spawnProcess. It also has several higher-level APIs
built on top of this aimed at making certain common tasks more
convenient. There is also a third-party project called Ampoule which
provides a process pool to which it is is relatively straightforward to
send jobs and then collect their results.
Jean-Paul
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